Method of forming fine pattern

Abstract

There is provided a method of forming, on a substrate, a fine resist pattern comprising a step for forming a photosensitive layer by using a photo-sensitive composition comprising at least a compound generating an acid by irradiation of light and a fluorine-containing polymer, in which the fluorine-containing polymer is represented by the formula (1): -(M 1 )-(M 2 )-(A 1 )-   (1) wherein the structural unit M 1 is a structural unit derived from a fluorine-containing monomer, in which at least one fluorine atom is bonded to any of carbon atoms forming the polymer trunk chain, the structural unit M 2 is a structural unit having an aliphatic ring structure in the polymer trunk chain, the structural unit A 1 is a structural unit derived from a monomer copolymerizable with the monomers to introduce the structural units M 1 and M 2 , provided that at least any one of the structural units M 1 , M 2 and A 1 has an acid-reactive functional group Y, and contents of the structural units M 1 , M 2 and A 1 are from 1 to 99% by mole, from 1 to 99% by mole and from 0 to 98% by mole, respectively, and the polymer satisfies Equation (X): N T /(N C −N O +4N F 2 )≦2.0, wherein N T is a compositional average number of whole atoms constituting the fluorine-containing polymer, N C is a compositional average number of carbon atoms, N O is a compositional average number of oxygen atoms and N F is a compositional average number of fluorine atoms bonded to carbon atoms of the polymer trunk chain and bonded to carbon atoms forming an aliphatic ring structure among fluorine atoms which constitute the fluorine-containing polymer. In the method of forming a fine pattern, the photosensitive composition having high practicality and prepared using a material having high transparency against exposure light having a short wavelength such as F 2 laser beam is used as a resist.

1 . A method of forming a fine resist pattern comprising a step for forming a photosensitive layer on a substrate or on a given layer on the substrate by using a photosensitive composition comprising at least a compound generating an acid by irradiation of light and a fluorine-containing polymer, a step for exposing by selectively irradiating a given area of said photosensitive layer with energy ray, a step for heat-treating said exposed photosensitive layer, and a step for forming a fine pattern by developing said heat-treated photosensitive layer to selectively remove the exposed portion or un-exposed portion of said photo-sensitive layer; in which said fluorine-containing polymer is represented by the formula (1):  
       -(M 1 )-(M 2 )-(A 1 )-   (1)  
       wherein the structural unit M 1  is a structural unit derived from a fluorine-containing monomer, in which at least one fluorine atom is bonded to any of carbon atoms forming the polymer trunk chain, the structural unit M 2  is a structural unit having an aliphatic ring structure in the polymer trunk chain, 
 the structural unit A 1  is a structural unit derived from a monomer copolymerizable with the monomers to introduce the structural units M 1  and M 2 ,  
 provided that at least any one of the structural units M 1 , M 2  and A 1  has an acid-reactive functional group Y, and contents of the structural units M 1 , M 2  and A 1  are from 1 to 99% by mole, from 1 to 99% by mole and from 0 to 98% by mole, respectively, and  
 said polymer satisfies Equation (X):  
   N   T /( N   C   −N   O +4 N   F   2 )≦2.0   (X)  
 wherein N T  is a compositional average number of whole atoms constituting the fluorine-containing polymer, N C  is a compositional average number of carbon atoms, N O  is a compositional average number of oxygen atoms and N F  is a compositional average number of fluorine atoms bonded to carbon atoms of the polymer trunk chain and bonded to carbon atoms forming an aliphatic ring structure among fluorine atoms which constitute the fluorine-containing polymer.  
 
     
     
         2 . The method of forming a fine resist pattern of  claim 1 , wherein said fluorine-containing polymer is represented by the formula (2):  
       -(M 1 )-(M 2 - 1 )-(A 1 )-   (2)  
       wherein the structural unit M 2 - 1  is a structural unit having an aliphatic monocyclic structure in the polymer trunk chain, 
 the structural unit M 1  and A 1  are as defined in the formula (1), provided that at least any one of the structural units Ml, M 2 - 1  and A 1  has an acid-reactive functional group Y, and contents of the structural units M 1 , M 2 - 1  and A 1  are from 1 to 99% by mole, from 1 to 99% by mole and from 0 to 98% by mole, respectively.  
 
     
     
         3 . The method of forming a fine resist pattern of  claim 1 , wherein said fluorine-containing polymer is represented by the formula (3):  
       -(M 1 )-(M 2 - 2 )-(A 1 )-   (3)  
       wherein the structural unit M 2 - 2  is a structural unit having an aliphatic polycyclic condensed structure in the polymer trunk chain, in which at least one fluorine atom and/or a fluorine-containing alkyl group which has 1 to 10 carbon atoms and may have ether bond is bonded to any of carbon atoms forming the aliphatic ring structure, 
 the structural unit M 1  and A 1  are as defined in the formula (1),  
 provided that at least any one of the structural units M 1 , M 2 - 2  and A 1  has an acid-reactive functional group Y, and contents of the structural units M 1 , M 2 - 2  and A 1  are from 1 to 99% by mole, from 1 to 99% by mole and from 0 to 98% by mole, respectively.  
 
     
     
         4 . The method of forming a fine resist pattern of  claim 1 , wherein the structural unit M 1  is a structural unit which is derived from at least one monomer selected from the group consisting of fluorine-containing ethylenic monomers having 2 or 3 carbon atoms and having at least one fluorine atom bonded to any of carbon atoms forming a trunk chain.  
     
     
         5 . The method of forming a fine resist pattern of  claim 4 , wherein the structural unit M 1  is a structural unit derived from at least one monomer selected from the group consisting of tetrafluoroethylene and chlorotrifluoroethylene.  
     
     
         6 . The method of forming a fine resist pattern of  claim 1 , wherein each atom of the fluorine-containing polymer satisfies Equation (X2):  
         N   T /( N   C   −N   O +4 N   F   2 )≦1.50   (X2).  
     
     
         7 . The method of forming a fine resist pattern of  claim 1 , wherein F 2  laser beam is used as said energy ray.  
     
     
         8 . The method of forming a fine resist pattern of  claim 1 , wherein ArF laser beam is used as said energy ray.  
     
     
         9 . The method of forming a fine resist pattern of  claim 1 , wherein KrF laser beam is used as said energy ray.  
     
     
         10 . The method of forming a fine resist pattern of  claim 1 , wherein high energy electron beam is used as said energy ray.  
     
     
         11 . The method of forming a fine resist pattern of  claim 1 , wherein high energy ion beam is used as said energy ray.  
     
     
         12 . The method of forming a fine resist pattern of  claim 1 , wherein X-ray is used as said energy ray.  
     
     
         13 . A method of forming a fine circuit pattern comprising, after forming the fine resist pattern by the method of  claim 1  on a substrate or on a given layer on the substrate, a step for forming an intended circuit pattern by etching said substrate or said given layer through the fine resist pattern.